Time-gated SERS sensors to decode temporal information within a single measurement

In fifteen words or less, explain the significance of this contribution (Novel Aspect).: A time-encoding mechanism to allow for temporal resolution in reagentless SERS sensors.

Abstract Text:

SERS sensors are challenging to use for continuous monitoring due to two main issues: -1- the size of current portable Raman systems, which cannot yet be easily used in wearable devices, and -2- the length/effects of SERS measurements, which often requires long laser exposures. These issues prevent reagentless SERS sensors to be used to obtain temporal information at high resolution. Such information can include concentration gradients and trends of biomarkers or contaminants, depending on the application. For example, current reagentless SERS sensors cannot differentiate between a constant analyte concentration or a sudden spike that integrate to the same value. Previous work on dissipative systems and sensing has shown the ability of activating sensors only after a specific lag time. This work demonstrated how toehold-mediated strand displacement mechanisms can be delayed by hybridizing an RNA strand on the toehold, which can be enzymatically degraded. This delay time can be tuned by controlling the different elements. Our goal is to exploit a dissipative system on multiplexed reagentless SERS sensors, to collect sensing data with temporal information encoded as different Raman reporters. Herein, we first demonstrate a dissipative sensing mechanism applied to a reagentless SERS sensors to delay activation. Further, we develop a second mechanism using the same principle to permanently deactivate the sensors. The combination of these mechanisms creates tunable time windows -time-gated sensors- in which these sensors are active. We then combined multiple windows using multiplexed sensors, to create an assay that can gives temporal information with a single measurement taken at the end.